arnold



(No Model.) 2 lSheets--Sheet 1.

W. S. ARNOLD.

STEAMl ENGINE. No. 310,489. Patentedv Jan. 6, 1885.`

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(No Model.) 2 Sheets-Sheet 2.

"W. s. ARNOLD.

STEAM ENGINE.

No. 310,489. Patented Jan. 6, 1885.

wznesses Y I Invener L//'Horny UNITED STATES PATENT OFFICE.

VILLIAM SAXON ARNOLD, OF CHATHAM, ONTARIO, CANADA.

STEAM-ENGINE.

SFECIFICATION forming part of Letters Patent No. 310,489, dated January6, 1885.

Application filed March 31,1884. (Xo model.)

To all whom, t may concern:

Beit known that I, WILLIAM Saxon AR- NOLD, a citizen of Canada, residingat Chatham, in the county of Kent and Province of Ontario, Canada, haveinvented a-new and useful Steam-Engine, of which the following is aspecification.

My invention relates to improvements in steam engines in which steam isused eXpansively, and the crank is used as a medium for convertingthereciprocating motion of the piston into the rotary motion of thecrank-shaft.

In engines using steam expansively by cutting off early in their stroke,the pressure is greatly reduced in the cylindcrsoon after cutting offand before the crank is in the best position for work, and the objectsof my improvements are, first, to apply the power which is transmittedthrough the piston to the crank when said crank is in a moreadvantageous position to transmit power than with the present practice;second, I avoid compression on exhaust side of cylinder, and

thereby prevent accidents from the accu1nu` lation ot' water. I attainthese objects by the mechanism illustrated in the accompanying drawings,in which- Figure l is a longitudinal section of cylinder, steam-chest,and pistons. Fig. 2 isatop view of cylinder, steam-chest, side bars,crossliead, and piston-rods as they appear after the removal ofsteam-chest cover and valve. Fig. 3 is a plan of the entire engine. Fig.4 is an enlarged-scale side elevation of the cammotion. Fig. 5 is anenlarged elevation of the slotted rocking lever, with its sliding block,wrist-pins, and connecting-rod.

Similarletters refer to si mi lar parts throughout the several views.

Cylinder A, with the steam-chest M, steamports N, exhaust-ports O, andexhaust-pipe P, constitute the cylinder proper of the engine. Thecylinder is provided with three pistons, the center one being the mainpiston B, andis connected to the main piston-rod E, which transmitspower to the crank with the usual connections. The movable piston headsC and I) are externally connected to each other by means of the endpiston-rods, F F F, cross-heads G G, and side bars, H H. The side bars,H H, are provided with wrist-pins I l, to w ich connecting-rodsmm areattached,

that have a reciprocating motion adapted to the time and travel of thepiston-heads C D. The slide-valve L controls the admission of steamonly, and through its valve-rod Kis operated by any suitable system ofexpansiongear. The exhaust-ports O O are so situated in the bottom ofcylinder that the pistonheads O D in their travel control the'eXit ofsteam. In the center of piston-head Gis an ordinary stuffing-box, U,through which the main piston-rod E passes. Vhen in operation, the mainpiston B makes aportion of its stroke before steam is admitted to thecylinder; the piston-heads O D, having simultaneously traveled the samedistance and in the same direction, then stop, and are firmly held inplace. This position is show n in the drawings, Fig. 1, the dotted linesdesignating the reverse position of main piston and pistonheads. Theexhaust-port O being uncovered by piston-head1) and steam then admittedby the steam-valve L, the main piston B continues the remainder of itsstroke.

The piston-heads() D are held in position and operated as follows: Onthe main crankshaft a is secured the disk Z1, on which is a segmentalprojection, c. Against the face of disk Z), and free to slide across thediameter of shaft c, is the plate d, which is provided with twosegmental projections, c c". To the plate d is attached one end ot' therod g, the other end connecting with the pin lz. This pin 7L projectsfrom the side of the upper end of a slotted rocking lever, i, the lowerend of rocking lever being pivoted from the bed-plateof engine bythepivot a. Across the end ot' engine bed-plate farthest from the shafta is jonrnaled the small crank-shaft k, said crankshaft being providedat each end with cranks Z Z and wrist-pins o p. Frein pins o p areconnecting-rods m m, which connect with wrist-pins I l on the side bars,H H. The wrist-pin p is extended through the sliding block j, the saidblock being free to slide in the slot of the rocking lever fz. 'Vhen themain piston B is at that end of the cylinder nearest to the main shaft,the projection c on disk b comes in Contact with the projection c on theplate (l, thereby causing the plate d to move toward the cylinder. Thismotion is transmitted to t-he rocking lever t' by the connecting-rod g.The said levert' will, there- IOO fore, through the medium of thesliding block I j and eXtended wrist-pin l), throw the crankshaft k onehalf-revolution, and thus (as the wrist-pins o p and I I are connectedby the rods m on) give proper motionto the pistonheads C D. When the endot' the projection c on the disk b ceases its contact with the end ofthe projection c on the plate d, the outer circumference of theprojection c revolves against the inner circumference of the projectionc, and thereby prevents motion in the plate d until the projection ccomes in contact with the lower projection, e, on the plate d. At thepoint where the segmental projection c on the disk b ceases its contactwith the end of the projection c the cranks ZZ have been thrown to theiropposite extremes, and the piston-heads C D have reached the extent oftheir travel and are held rigid in place, owing to the position of thecranks ZZ. It is at this point steam is admitted to the cylinder. Thereturn-stroke is performed in a similar manner to the foregoing by thesegmental projection c on the disk b coming in contact with the lowerprojection, e, on the plate d.

I am aware that prior to my invention steam-engines have been made withmore th an one piston and with separate steam and exhaust ports. Itherefore do not claim such a combination, broadly; but

I I, the cross-heads G G, carried by said side I bars, the piston-rods FF F. secured to crossheads G G, the piston-heads C D, secured topiston-rods F F F, all having an intermitting reciprocating motionderived from and operated by the mechanism consisting of the disk b,with its projection e, said disk being secured to the shaft c, the plateel, with its projections c e, the rod g, which connects the plate d tothe upper end of the slotted rocking lever t', the sliding block .7',the wrist-pins o p, the cranks Z Z, the crank-shaft k, and theconnecting-rods m m, which connect the wrist-pins o p with thewrist-pins I I on the side bars, H H, all substantially as described,for the purposes speciiied.

2. In a steam-engine cylinder, the combination of the piston-heads C Dwith the steamports N N and the exhaust-ports O O, substantially asshown, and for the purposes specified.

WILLIAM SAXON ARNOLD.

Vitn esses XV. F. RUTLnY, T. J. A. RU'rLnY.

